Waste lithium battery black powder pretreatment method

Abstract

The invention provides a waste lithium battery black powder pretreatment method. The waste lithium battery black powder pretreatment method comprises the following steps: (a) emptying: filling waste lithium battery black powder into a pretreatment reactor, and introducing nitrogen or inert gas for emptying; (b) preheating: respectively preheating the waste lithium battery black powder and the non-oxidizing carrier gas; (c) pretreatment: continuously introducing the preheated carrier gas into the pretreatment reactor, mixing the preheated carrier gas with the preheated battery black powder, heating, and carrying out heat preservation reaction for a certain time t; (d) cooling: closing a heating device of the pretreatment reactor, stopping introducing the preheated carrier gas, continuously introducing nitrogen or inert gas into the pretreatment reactor, and gradually cooling the battery black powder in the pretreatment reactor; and (e) unloading: when the battery black powder in the pretreatment reactor is cooled to be less than 50 DEG C, unloading to obtain the pretreated battery black powder. The method disclosed by the invention is simple and controllable in process, and has the advantages of high defluorination rate, high efficiency, short process and low cost.

Description

Technical Field

[0001] The invention relates to the field of battery recycling, and in particular to a method for pretreating black powder from waste lithium batteries. Background Art

[0002] Lithium batteries are widely used in 3C, pure electric vehicles, electrochemical energy storage and other fields due to their advantages such as high specific energy, long cycle life and reasonable cost. With the large-scale application of lithium batteries, the recycling and reuse of waste lithium batteries has become more and more important and urgent.

[0003] In the process of recycling and reusing waste lithium batteries, there is often a common technical problem, that is, the removal of fluorine from waste lithium batteries. The fluorine contained in waste lithium batteries generally comes from two parts: one is the fluorine-containing electrolyte, such as lithium hexafluorophosphate; the other is the fluorine-containing binder, such as PVDF.

[0004] At present, the removal of fluorine from waste lithium batteries is generally done by low-temperature volatilization and high-temperature pyrolysis. Low-temperature volatilization takes advantage of the low decomposition temperature of lithium hexafluorophosphate, which decomposes into gaseous phosphorus fluoride and solid LiF at about 150°C. This method can generally achieve more than half of the fluorine in the electrolyte to be removed with the gas phase. High-temperature pyrolysis utilizes the thermal cracking of PVDF under high temperature conditions to produce hydrogen fluoride gas to remove fluorine in the binder with the gas phase. In addition, there are other methods such as alkaline defluorination by immersion in aqueous solution or acidic roasting defluorination by adding acid.

[0005] The existing methods for pre-treatment and defluorination of waste lithium batteries have the following problems and shortcomings:

[0006] First, the defluorination rate is low. The existing defluorination method for pretreatment of waste lithium batteries has a low fluorine removal rate, and the residual fluorine content in the pretreated battery black powder can still reach more than 0.3%. In the subsequent material or element recovery process, the fluorine in the pretreated battery black powder with a high residual fluorine content enters the liquid phase, gas phase, and solid phase, bringing a series of separation and purification problems.

[0007] Second, the fluorine removal efficiency is low. Existing pretreatment defluorination methods, such as alkaline defluorination by immersion in aqueous solution, often require a long pretreatment defluorination time to achieve a predetermined defluorination rate, and the corresponding fluorine removal efficiency is low.

[0008] The third is high cost and poor economic efficiency. The existing pretreatment defluorination method has a low fluorine removal efficiency due to the high residual fluorine content in the battery black powder after pretreatment. If the alkaline defluorination is carried out by soaking in an aqueous solution, liquid alkali is still required. The residual fluorine in the battery black powder after pretreatment still needs to be further removed or separated in the subsequent recovery process, which leads to the high cost and poor economic efficiency of the existing pretreatment defluorination method.

[0009] Therefore, there is an urgent need to develop a high defluorination rate, high efficiency, and low-cost pretreatment technology for waste lithium battery black powder to maximize the recycling value of waste lithium iron phosphate batteries. Summary of the invention

[0010] In view of the shortcomings of the prior art, the present invention aims to provide a method for pretreating black powder from waste lithium batteries. The method has a simple and controllable process, and its purpose is to defluorinate the black powder from waste lithium batteries, thereby removing both organic solvents and binders. The method has the advantages of high defluorination rate, high efficiency, short process and low cost.

[0011] The present invention is achieved through the following solutions:

[0012] A method for pretreating black powder from waste lithium batteries comprises the following steps:

[0013] (a) Emptying: Loading the waste lithium battery black powder into the pretreatment reactor, and introducing nitrogen or inert gas into the pretreatment reactor for emptying until the oxygen content in the pretreatment reactor is less than 0.2%; the inert gas is generally one or more of helium and argon;

[0014] (b) Preheating: preheating the waste lithium battery black powder in a pretreatment reactor, wherein the temperature of the preheated waste lithium battery black powder reaches T_black, and the preheated battery black powder is obtained; preheating the non-oxidizing carrier gas in a carrier gas preheater, wherein the temperature of the preheated carrier gas reaches T_gas, and the preheated carrier gas is obtained; wherein T_black and T_gas satisfy: 110°C≤T_black≤200°C, 130°C≤T_gas≤400°C, and T_gas≥T_black;

[0015] (c) Pretreatment: The preheated carrier gas is continuously introduced into the pretreatment reactor to mix with the preheated battery black powder. The preheated carrier gas and the preheated battery black powder are heated in the pretreatment reactor until the temperature of the pretreatment reactor reaches T_target, and then the temperature is kept for a certain time t, wherein T_target satisfies: 500°C≤T_target≤850°C;

[0016] (d) Cooling: After the heat preservation reaction time is reached, the heating device of the pretreatment reactor is turned off, and the preheated carrier gas is stopped from being introduced into the pretreatment reactor. Then, nitrogen or inert gas is continuously introduced into the pretreatment reactor, and the battery black powder in the pretreatment reactor is gradually cooled down;

[0017] (e) Unloading: When the battery black powder in the pretreatment reactor is cooled to less than 50° C., the battery black powder is unloaded to obtain the pretreated battery black powder.

[0018] The tail gas generated during the entire process is treated by the tail gas treatment device and then discharged and recycled in compliance with the standards.

[0019] During the heat preservation reaction of the preheated carrier gas and the preheated battery black powder in the pretreatment reactor, the F contained in the waste lithium battery black powder reacts with the H formed by the cracking of the carrier gas to generate highly volatile hydrogen fluoride gas, which escapes quickly with the carrier gas, achieving the effect of efficient and deep removal of F from the waste lithium battery black powder. The chemical reaction formula is as follows:

[0020] F+H=HF↑ (1)

[0021] Further, the non-oxidizing carrier gas is a H-containing gas that can be cracked under T_target temperature conditions or a mixed gas of a H-containing gas that can be cracked under T_target temperature conditions and an inactive gas under T_target temperature conditions, and the partial pressure ratio P_ratio of the non-oxidizing carrier gas satisfies 0.05≤P_ratio≤1.0, P_ratio=P_H / P_Total, P_H is the pressure of the H-containing gas that can be cracked under T_target temperature conditions, and P_Total is the total pressure of the non-oxidizing carrier gas; the H-containing gas that can be cracked under T_target temperature conditions is one or more of hydrogen, methane, ethane, water vapor, methanol gas, ethanol gas, formic acid gas, acetic acid gas, methyl carbonate gas, ethyl methyl carbonate gas, ethyl carbonate gas, and dimethyl carbonate gas; the inactive gas under T_target temperature conditions is one or more of nitrogen, helium, and argon gas.

[0022] Furthermore, the heat preservation reaction time t is 5 to 180 minutes.

[0023] Furthermore, the gas-solid ratio GS_ratio of the non-oxidizing carrier gas to the waste lithium battery black powder satisfies 120≤GS_ratio≤6000, GS_ratio=V_ 气 / M,V_ 气 is the volume of the non-oxidizing carrier gas, in L; M is the weight of the waste lithium battery black powder, in kg. The increase of gas-solid ratio is conducive to reducing the partial pressure of hydrogen fluoride gas and increasing the activity of H, which is conducive to the chemical reaction formula (1) from left to right, so 120≤GS_ratio; however, increasing the gas-solid ratio will greatly increase the amount of non-oxidizing carrier gas consumed, and at the same time, the power consumption of heating the non-oxidizing carrier gas and maintaining the pretreatment reaction will greatly increase, which is not conducive to reducing the cost, so GS_ratio≤6000.

[0024] Furthermore, the filling rate R of the waste lithium battery black powder in the pretreatment reactor satisfies 5%≤R≤60%, R=M / (ρ×V_ 容 )×100%, where ρ is the bulk density of waste lithium battery black powder, in kg / m3; V_ 容is the volume of the pretreatment reactor, in m3; M is the mass of the waste lithium battery black powder, in kg. If the filling rate R is too small, the pretreatment reactor will process a small amount of waste lithium battery black powder per unit time, which is not conducive to improving processing efficiency and reducing processing costs. Therefore, the lower limit of the filling rate R is set to 5%; however, the filling rate R cannot be too large. An excessive filling rate is not conducive to the contact and uniform mixing of gas-solid substances, and is also not conducive to the rapid escape of the generated hydrogen fluoride gas. Therefore, the upper limit of the filling rate R is set to 60%.

[0025] The method for pretreating black powder from waste lithium batteries of the present invention has a simple and controllable process and has the following advantages:

[0026] 1. High defluorination rate: The present invention adopts a medium-temperature carrier gas roasting method to promote the combination of fluorine elements and H free radicals in waste lithium battery black powder to generate hydrogen fluoride gas by strengthening heat and mass transfer, and quickly removes it from the solid phase of waste lithium battery black powder through carrier gas, so that the residual fluorine content in the pretreated battery black powder can be less than 0.05%;

[0027] 2. High efficiency: The present invention first preheats the waste lithium battery black powder and the carrier gas, and then performs mixed heating and heat preservation pretreatment. By controlling the reaction temperature, reaction time, gas-solid ratio, filling rate, etc., the high-efficiency pretreatment of the waste lithium battery black powder is achieved. Under the premise of achieving a high defluorination rate, the fastest pretreatment time is only about 5 minutes;

[0028] 3. Low cost: The present invention directly uses a medium-temperature carrier gas roasting method to achieve high-efficiency deep pretreatment defluorination. The process flow is short and there is no lengthy treatment process such as leaching, filtering, and washing required for alkaline defluorination by immersion in aqueous solution. There is no need to consume relatively expensive chemical reagents, thereby greatly reducing the cost of pretreatment defluorination of waste lithium battery black powder. Compared with the existing traditional process, the present invention has a significant cost advantage. In addition, the pretreatment defluorination method of the present invention does not introduce new inorganic anions and metal cations, which is very beneficial to reduce the difficulty of impurity removal, purification, and separation of the pretreated battery black powder in the subsequent recovery process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 This is a process flow chart of a method for pretreating black powder from waste lithium batteries in the present application. DETAILED DESCRIPTION

[0030] The present invention is further described below in conjunction with embodiments and drawings, but the present invention is not limited to the description of the embodiments.

[0031] Example 1

[0032] A method for pretreating black powder from waste lithium batteries, the process flow is as follows: Figure 1 As shown, the following steps are included:

[0033] (a) Emptying: 100 kg of waste lithium battery black powder with a bulk density of 0.70 kg / L and a fluorine content of 2.8% is loaded into the pretreatment reactor, that is, the filling rate R of the waste lithium battery black powder in the pretreatment reactor is 25.5%, and nitrogen is introduced into the pretreatment reactor for emptying until the oxygen content in the pretreatment reactor is less than 0.2%;

[0034] (b) Preheating: preheating the waste lithium battery black powder in a pretreatment reactor, the temperature of the preheated waste lithium battery black powder reaches T_black, T_black is 110°C, and the preheated battery black powder is obtained; preheating the non-oxidizing carrier gas in a carrier gas preheater, the non-oxidizing carrier gas in this embodiment is a mixed gas of methanol gas and nitrogen, the partial pressure ratio of the non-oxidizing carrier gas P_ratio is 0.78, the preheated carrier gas temperature reaches T_gas, T_gas is 150°C, and the preheated carrier gas is obtained;

[0035] (c) Pretreatment: 80000L of preheated carrier gas is continuously introduced into the pretreatment reactor to mix with the preheated battery black powder, that is, the gas-solid ratio GS_ratio of the non-oxidizing carrier gas to the waste lithium battery black powder is controlled to be 800L / kg, and the preheated carrier gas and the preheated battery black powder are heated in the pretreatment reactor until the temperature of the pretreatment reactor reaches T_target, T_target is 650°C, and then the temperature is kept for a certain time t, and the temperature is kept for 30min;

[0036] (d) Cooling: After the heat preservation reaction time t is reached, the pretreatment reactor heating device is turned off, and the preheated carrier gas is stopped from being introduced into the pretreatment reactor. Then, nitrogen is continuously introduced into the pretreatment reactor, and the battery black powder in the pretreatment reactor is gradually cooled down;

[0037] (e) Unloading: When the battery black powder in the pretreatment reactor is cooled to less than 50° C., the battery black powder is unloaded to obtain the pretreated battery black powder.

[0038] The tail gas generated during the entire process is treated by the tail gas treatment device and then discharged and recycled in compliance with the standards.

[0039] Example 2

[0040] A method for pretreating black powder from waste lithium batteries, the process flow is as follows: Figure 1 As shown, the following steps are included:

[0041] (a) Emptying: 150 kg of waste lithium battery black powder with a bulk density of 0.85 kg / L and a fluorine content of 3.1% is loaded into the pretreatment reactor, that is, the filling rate R of the waste lithium battery black powder in the pretreatment reactor is 31.5%, and nitrogen is introduced into the pretreatment reactor for emptying until the oxygen content in the pretreatment reactor is less than 0.2%;

[0042] (b) Preheating: preheating the waste lithium battery black powder in a pretreatment reactor, the temperature of the preheated waste lithium battery black powder reaches T_black, T_black is 150°C, and the preheated battery black powder is obtained; preheating the non-oxidizing carrier gas in a carrier gas preheater, the non-oxidizing carrier gas in this embodiment is a mixed gas of ethyl methyl carbonate gas and nitrogen, the partial pressure ratio of the non-oxidizing carrier gas P_ratio is 0.62, the temperature of the preheated carrier gas reaches T_gas, T_gas is 260°C, and the preheated carrier gas is obtained;

[0043] (c) Pretreatment: 180000L of preheated carrier gas is continuously introduced into the pretreatment reactor to mix with the preheated battery black powder, that is, the gas-solid ratio GS_ratio of the non-oxidizing carrier gas to the waste lithium battery black powder is controlled to be 1200L / kg, and the preheated carrier gas and the preheated battery black powder are heated in the pretreatment reactor until the temperature of the pretreatment reactor reaches T_target, T_target is 800°C, and then the temperature is kept for a certain time t, and the temperature is kept for 15min;

[0044] (d) Cooling: After the heat preservation reaction time t is reached, the pretreatment reactor heating device is turned off, and the preheated carrier gas is stopped from being introduced into the pretreatment reactor. Then, nitrogen is continuously introduced into the pretreatment reactor, and the battery black powder in the pretreatment reactor is gradually cooled down;

[0045] (e) Unloading: When the battery black powder in the pretreatment reactor is cooled to less than 50° C., the battery black powder is unloaded to obtain the pretreated battery black powder.

[0046] The tail gas generated during the entire process is treated by the tail gas treatment device and then discharged and recycled in compliance with the standards.

[0047] Example 3

[0048] A method for pretreating black powder from waste lithium batteries, the process flow is as follows: Figure 1 As shown, the following steps are included:

[0049] (a) evacuation: 220 kg of waste lithium battery black powder, with a bulk density of 0.67 kg / L and a fluorine content of 3.35% are loaded into the pretreatment reactor, i.e., the filling rate R of the waste lithium battery black powder in the pretreatment reactor is 58.6%, and helium is introduced into the pretreatment reactor for evacuation until the oxygen content in the pretreatment reactor is less than 0.2%;

[0050] (b) Preheating: preheating the waste lithium battery black powder in a pretreatment reactor, wherein the temperature of the preheated waste lithium battery black powder reaches T_black, wherein T_black is 200°C, and the preheated battery black powder is obtained; preheating the non-oxidizing carrier gas in a carrier gas preheater, wherein the non-oxidizing carrier gas in this embodiment is a mixed gas of water vapor and helium, wherein the partial pressure ratio of the non-oxidizing carrier gas is 0.89, and the temperature of the preheated carrier gas reaches T_gas, wherein T_gas is 400°C, and the preheated carrier gas is obtained;

[0051] (c) Pretreatment: 77000L of preheated carrier gas is continuously introduced into the pretreatment reactor to mix with the preheated battery black powder, that is, the gas-solid ratio GS_ratio of the non-oxidizing carrier gas to the waste lithium battery black powder is controlled to be 350L / kg, and the preheated carrier gas and the preheated battery black powder are heated in the pretreatment reactor until the temperature of the pretreatment reactor reaches T_target, T_target is 720°C, and then the temperature is kept for a certain time t, and the temperature is kept for 40min;

[0052] (d) Cooling: After the heat preservation reaction time t is reached, the pretreatment reactor heating device is turned off, and the preheated carrier gas is stopped from being introduced into the pretreatment reactor. Then, helium is continuously introduced into the pretreatment reactor, and the battery black powder in the pretreatment reactor is gradually cooled down;

[0053] (e) Unloading: When the battery black powder in the pretreatment reactor is cooled to less than 50° C., the battery black powder is unloaded to obtain the pretreated battery black powder.

[0054] The tail gas generated during the entire process is treated by the tail gas treatment device and then discharged and recycled in compliance with the standards.

[0055] Example 4

[0056] A method for pretreating black powder from waste lithium batteries, the process flow is as follows: Figure 1 As shown, the following steps are included:

[0057] (a) Emptying: Loading the waste lithium battery black powder with a mass of 25 kg, a bulk density of 0.76 kg / L, and a fluorine content of 2.92% into the pretreatment reactor, that is, the filling rate R of the waste lithium battery black powder in the pretreatment reactor is 5.9%, and introducing nitrogen into the pretreatment reactor for emptying until the oxygen content in the pretreatment reactor is less than 0.2%;

[0058] (b) Preheating: preheating the waste lithium battery black powder in a pretreatment reactor, the temperature of the preheated waste lithium battery black powder reaches T_black, T_black is 180°C, and the preheated battery black powder is obtained; preheating the non-oxidizing carrier gas in a carrier gas preheater, the non-oxidizing carrier gas in this embodiment is hydrogen, the partial pressure ratio of the non-oxidizing carrier gas P_ratio is 1.0, the temperature of the preheated carrier gas reaches T_gas, T_gas is 300°C, and the preheated carrier gas is obtained;

[0059] (c) Pretreatment: 3750 L of preheated carrier gas is continuously introduced into the pretreatment reactor to mix with the preheated battery black powder, that is, the gas-solid ratio GS_ratio of the non-oxidizing carrier gas to the waste lithium battery black powder is controlled to be 150 L / kg, and the preheated carrier gas and the preheated battery black powder are heated in the pretreatment reactor until the temperature of the pretreatment reactor reaches T_target, T_target is 750°C, and then the temperature is kept for a certain time t, and the temperature is kept for 5 min;

[0060] (d) Cooling: After the heat preservation reaction time t is reached, the pretreatment reactor heating device is turned off, and the preheated carrier gas is stopped from being introduced into the pretreatment reactor. Then, nitrogen is continuously introduced into the pretreatment reactor, and the battery black powder in the pretreatment reactor is gradually cooled down;

[0061] (e) Unloading: When the battery black powder in the pretreatment reactor is cooled to less than 50° C., the battery black powder is unloaded to obtain the pretreated battery black powder.

[0062] The tail gas generated during the entire process is treated by the tail gas treatment device and then discharged and recycled in compliance with the standards.

[0063] Example 5

[0064] A method for pretreating black powder from waste lithium batteries, the process flow is as follows: Figure 1 As shown, the following steps are included:

[0065] (a) Emptying: 150 kg of waste lithium battery black powder with a bulk density of 0.72 kg / L and a fluorine content of 3.22% is loaded into the pretreatment reactor, that is, the filling rate R of the waste lithium battery black powder in the pretreatment reactor is 37.2%, and nitrogen is introduced into the pretreatment reactor for emptying until the oxygen content in the pretreatment reactor is less than 0.2%;

[0066] (b) Preheating: preheating the waste lithium battery black powder in a pretreatment reactor, the temperature of the preheated waste lithium battery black powder reaches T_black, T_black is 130°C, and the preheated battery black powder is obtained; preheating the non-oxidizing carrier gas in a carrier gas preheater, the non-oxidizing carrier gas in this embodiment is a mixed gas of ethane and nitrogen, the partial pressure ratio of the non-oxidizing carrier gas P_ratio is 0.15, the temperature of the preheated carrier gas reaches T_gas, T_gas is 220°C, and the preheated carrier gas is obtained;

[0067] (c) Pretreatment: 90000L of preheated carrier gas is continuously introduced into the pretreatment reactor to mix with the preheated battery black powder, that is, the gas-solid ratio GS_ratio of the non-oxidizing carrier gas to the waste lithium battery black powder is controlled to be 600L / kg, and the preheated carrier gas and the preheated battery black powder are heated in the pretreatment reactor until the temperature of the pretreatment reactor reaches T_target, T_target is 500°C, and then the temperature is kept for a certain time t, and the temperature is kept for 60min;

[0068] (d) Cooling: After the heat preservation reaction time t is reached, the pretreatment reactor heating device is turned off, and the preheated carrier gas is stopped from being introduced into the pretreatment reactor. Then, nitrogen is continuously introduced into the pretreatment reactor, and the battery black powder in the pretreatment reactor is gradually cooled down;

[0069] (e) Unloading: When the battery black powder in the pretreatment reactor is cooled to less than 50° C., the battery black powder is unloaded to obtain the pretreated battery black powder.

[0070] The tail gas generated during the entire process is treated by the tail gas treatment device and then discharged and recycled in compliance with the standards.

[0071] The residual fluorine content of the pretreated battery black powder obtained in Examples 1 to 5 was tested respectively, and the defluorination rate of each example was calculated. The specific data are shown in Table 1.

[0072] Table 1 Data on residual fluorine content in battery black powder after pretreatment

[0073] Residual fluorine content Defluorination rate Example 1 0.045％ 98.4％ Example 2 0.032％ 99.0％ Example 3 0.048％ 98.6％ Example 4 0.043％ 98.5％ Example 5 0.040％ 98.8％

[0074] It can be seen from the data in Table 1 that the residual fluorine content in the pretreated battery black powder obtained in Example 1, Example 2, Example 3, Example 4 and Example 5 is less than 0.05%, which is much lower than the residual fluorine content in the battery black powder obtained after defluorination using the prior art (more than 0.3%). The defluorination rate of each embodiment reaches more than 98%.

Claims

1. A method for pretreating black powder from waste lithium batteries, characterized in that: The steps include: (a) Emptying: Loading the waste lithium battery black powder into the pretreatment reactor, and introducing nitrogen or inert gas into the pretreatment reactor for emptying until the oxygen content in the pretreatment reactor is less than 0.2%; (b) preheating: preheating the waste lithium battery black powder in a pretreatment reactor until the temperature of the preheated waste lithium battery black powder reaches T_black, thereby obtaining preheated battery black powder; preheating the non-oxidizing carrier gas in a carrier gas preheater until the temperature of the preheated carrier gas reaches T_gas, thereby obtaining preheated carrier gas; wherein T_black, T_gas meet: 110℃≤T_black≤200℃, 130℃≤T_gas≤400℃, and T_gas ≥ T_black; (c) Pretreatment: The preheated carrier gas is continuously introduced into the pretreatment reactor to mix with the preheated battery black powder. The preheated carrier gas and the preheated battery black powder are heated in the pretreatment reactor until the temperature of the pretreatment reactor reaches T_target, and then the temperature is kept for a certain time t, wherein T_target satisfies: 500°C≤T_target≤850°C; (d) Cooling: After the heat preservation reaction time is reached, the heating device of the pretreatment reactor is turned off, and the preheated carrier gas is stopped from being introduced into the pretreatment reactor. Then, nitrogen or inert gas is continuously introduced into the pretreatment reactor, and the battery black powder in the pretreatment reactor is gradually cooled down; (e) Unloading: When the battery black powder in the pretreatment reactor is cooled to less than 50° C., the battery black powder is unloaded to obtain the pretreated battery black powder.

2. A method for pretreating black powder from waste lithium batteries as claimed in claim 1, characterized in that: The non-oxidizing carrier gas is a H-containing gas that can be cracked under the T_target temperature condition or a mixed gas of a H-containing gas that can be cracked under the T_target temperature condition and an inactive gas under the T_target temperature condition, and the partial pressure ratio P_ratio of the non-oxidizing carrier gas satisfies 0.05≤P_ratio≤1.0, P_ratio=P_H / P_Total, P_H is the pressure of the H-containing gas that can be cracked under the T_target temperature condition, and P_Total is the total pressure of the non-oxidizing carrier gas; the H-containing gas that can be cracked under the T_target temperature condition is one or more of hydrogen, methane, ethane, water vapor, methanol gas, ethanol gas, formic acid gas, acetic acid gas, methyl carbonate gas, ethyl methyl carbonate gas, ethyl carbonate gas, and dimethyl carbonate gas; the inactive gas under the T_target temperature condition is one or more of nitrogen, helium, and argon gas.

3. A method for pretreating black powder from waste lithium batteries as claimed in claim 1, characterized in that: The heat preservation reaction time t is 5 to 180 minutes.

4. A method for pretreating black powder from waste lithium batteries as claimed in any one of claims 1 to 3, characterized in that: The gas-solid ratio GS_ratio of the non-oxidizing carrier gas to the waste lithium battery black powder satisfies 120≤GS_ratio≤6000, GS_ratio=V_ 气 / M,V_ 气 is the volume of non-oxidizing carrier gas, in L; M is the weight of black powder from waste lithium batteries, in Kg.

5. A method for pretreating black powder from waste lithium batteries as claimed in any one of claims 1 to 3, characterized in that: The filling rate R of the waste lithium battery black powder in the pretreatment reactor satisfies 5%≤R≤60%, R=M / (ρ×V_ 容 )×100%, where ρ is the bulk density of waste lithium battery black powder, in kg / m 3 ; V_ 容 is the volume of the pretreatment reactor, in m 3 ; M is the mass of black powder from waste lithium batteries, in kg.

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